For therapeutic ultrasound, real-time monitoring of a biological object being treated is of critical importance to the patient's safety and the success of the procedure or operation. While magnetic resonance imaging (MRI) and non-invasive ultrasound imaging have been conventionally used for this purpose, they provide a limited viewing angle and/or images with limited spatial resolution. For many high-precision invasive operations, such as, for example, peripheral thrombolysis, in-situ imaging capability is highly desired.
Some conventional capacitive micromachined ultrasonic transducers insert a dielectric layer between the electrode on the membrane and its counter electrode to prevent the membrane electrode from contacting the counter electrode in a collapse event such as, for example, during an ultrasound transduction. However, the dielectric layer insert between the membrane and the counter electrode increases the effective gap height of the capacitive micromachined ultrasonic transducer, as well as the voltage required to drive the transducer. It may be desirable to minimize the gap height and the required driving voltage of a capacitive micromachined ultrasonic transducer so that the transducer can be employed in minimally-invasive or non-invasive applications, treatments, and/or operations, such as, for example, intravascular procedures including, but not limited to, peripheral thrombolysis
This disclosure solves one or more of the aforesaid problems with a therapeutic ultrasound transducer chip having built-in imaging capability and/or a reduced gap height and/or driving voltage.